Surface treatment of halogenated fluoroethylenes and laminates thereof



June 2l, 1960 R. P. cox r-:rAL 2,941,912

SURFACE TREATMENT OF' HALOGENATED FLUOROETHYLENES AND LAMINATES THEREOF Original Filed March 24, 1953 FIGJ \\\\ EATE E HALOGENAT POLY T LENS ,Mms

SURFACE TREATMENTE GF HALGENATED FLUROETHYLENES AND LAMINATES THEREOF Roberti. Cox, Luther L. Yaeger, and Ralph W. Buetow, Madison, Wis., assign'ors to Pittsburgh Piate Giese Company Original application Mar. 24, 1953, Ser. No. 344,398,

n oW Patent B lo. 2,788,36, dated Apr. 9, 1957. Diriitond this application Sept. 25, 1956, Ser. No.

22 Claims. (Cl. 154-443) l This invention relates to an improved method for treating the surfaces of certain non-polar substances to render them suitable for adhesion to other substances and to various practical applications thereof, such as applying a superior thin non-corrosive coating to surfaces of V resistance to physical and chemical changes. These characteristics render these substances likely for use as corrosiers-resistant coatings for other materials subject to corrosion. However, these non-polar compounds have not been adhered adequately to other substances heretofore by means of conventional adhesives nor have they been effectively bonded to other materials except under conditions of high temperatures and pressures wherein the materials being coated are subject to physical or chemical change deleterious to the material before the bond is effected. Hence, these non-polar compounds have never been utilized previously to their fullest capabilities.

Accordingly, it is an object of the present invention to provide a method for imparting a protective coating to the surface of a material subject to chemical corrosion.

Another object of the present invention is to provide a method of treating certain organic substances to render them amenable for adhesive bonding by means of presently known adhesives to the surface of other substances.

Still another object of the present invention is to provide laminated articles, the laminations of which are firmly bonded by the method taught by the present invention.

It is still another object of the present invention to provide a novel container for corrosive materials wherein the teachings of the present invention are utilized to provide a non-corrosive coating for the container.

These and other objects of the present invention will become apparent upon further study of the following description. It is to be understood, however, that the description contained herein is for purposes of illustration only, and that the scope of the invention is limited only by the extent of the appended claims.

In the drawing, which is to be considered part of the description of this invention, Figure l discloses a crosssectional view of one practical application of the present invention wherein a polymeric halogenated ethylene, not subject to corrosion and comprising no less than two nor more than three iluorine atoms per monomer, is treated on one surface in accordance with the teachings of the present invention to enable that surface to be adhered to an exposed surface of a material that is subject to corrosion, Figure 2 discloses a cross-sectional ICC View of another practical embodiment of the present invention Iwherein a sheet of a polymeric halogenated cornpound such as depicted in Figure l is rendered suitable for use as an interlayer for a laminated window closure comprising two sheets of either glass `or a transparent synthetic material by treating -both surfaces of the interlayer in accordance with the teachings of the present invention, thereby rendering it possible to adhere both surfaces of the interlayer in accordance with the teachings of the present invention, i.e., therebyrendering it possible to adhere both surfaces of the halogenated polyethylene compound to individual sheets of the transparent material by means of a suitable adhesive, and Figure 3 represents a cross-sectional view ofanother practical embodiment of the present invention, namely, a container for corrosive reagents such as fuming nitric acid, wherein at least the inner surface of the container is coated vwith a halogenated polyethylene in accordance with the teachings of the present invention.

It has been discovered thatby modification of their surfaces, certain halogenated polyethylenes having the general formula (-C2FnX4 -)m,` where m is any whole number, n equals 2 or -3 and 'X represents a halogen other than uorine, can be adhered to other substances by treatment with a phosphite.

lt was discovered that by reacting a surface of halogenated polyethylene with a phosphite which could later react further with a wide variety of conventional adhesives, the halogenated ethylene polymer can be adhered to a wide variety of substances subject to corrosion on exposure tov corrosive agents. Such substances include yglass, polymethyl methacrylate (Lucite), polymethyl alpha chloro acrylate (Gante), cellulosic niaterialssuch as wood and metals, such as aluminum.

The phosphites which may be utilized include aliphatic orY aromatic phosphites such as di Z-ethyl hexyl phosphite, diallyl phosphite, di beta chloro allyl phosphite, di vinyl phosphite, mono allyl phosphite, di ethyl phosphite, diphenyl phosphite, phenyl methyl phosphite,

etc.

The halogenated polyethylenes that are modied by the phosphite treatments listed above include poly triuoro chloro ethylene, poly tn'fluoro bromo ethylene, poly trifluoro iodo ethylene, poly difluoro dichlcro ethylene, poly difluoro dibromo ethylene, poly difluoro diiodo ethylene, poly diuoro chloro bromo ethylene, poly diuoro chloro iodo ethylene and poly diuoro bromo iodo ethylene. V

One of the aforementioned materials which is most suitable and presently available for use as a protective coating is polychlorotrifluoroethylene, known more commonly under the names Trithene or Kel-F. While this substance is impervious to chemical reaction with most reagents, its use as a protective coating has` beentlimited in the past due to the inability of the material to be bonded to substances liable to corrosion. s

Most any commercially available adhesive may be used to bond a treated halogenated ethylene surface to the surface of another substance. Typical adhesives suitable for use are disclosed in Patent No. 2,464,826 to Neher and Bauer, This patent teaches the kuse of acrylate adhesives. It is also understood that crotonate, methacrylate, alpha chloroacrylate, sorbate and furnarate adhesives are also suitable as ywell as other commercial types of adhesives, may be utilized as well as those disclosed in the aforementioned patents.

It is believed that the substitution of a iiuorine atom for a hydrogen in an ethylene compound results in such a strong bond that the tiuorine cannot be removed. It has been repeatedly demonstrated in the laboratory that a completely iiuorinated ethylene (C2F4) will not react. Prior to the presentV invention, it had been conatleast.;iattttttsbtataratt any haben Substituted ethylene, even those containing 2 or 3 iiuorine atoms substituted for the hydrogens.` However, the bond formed T-"gy Lawchloljine,bromide or iodine substituted atom has tenistas e bediente'asesinatos-byment f a 1213stichtte wp tpxtht Plrtttrizeftuofinated ethylene gnnomersujflhepresence o frtheduorine atoms in these ,rnonomers provides'ta compound that is Vnot susceptible of further reaction once the other halogens have'reacted.

l`he compounds containing the phsphite groups' capable "o f 'substitution in lieu ofthe halogens other than uor-ine inthe halogenated ,monomers of polyethylene-also contain @other reactiveY groups capable-ofeforming a bond With-an adhesiveeitherjby'polymerization -with an adhesive or by chemicalf'vreaction.

u-:The' followingmaterialsfand treatments provided good *adhesion properties toy Trithene:

.Y ;,`Alkylj'phosphitestsuchvas'- diethylfdibutyl,A dipropyl and ,-di `2-e`thy-l hexyl-phosphite: treatmentfof'tthe Trithene followedby'lamina'tes with 'conventional' adhesives.

The present invention contemplates lthe use of a phosphite for pretreting''thesurfaceof'certain halogenated "ipolyethyle'nesfndfmaking it receptive to available ad- ]hesives for dilerent -types'of material rather .than utilize'ing atspecicadhesive'fm each-diierent type of materialf requiring 'a protective coating.

adhesion" ofpreteated haiogenated `polyethylenes by `conventional adhesives tofthe Afoll'cntving materials Was e* accomplished: j"pol-yinethyl methacryIate, i polymethyl alphachl6roactylte"Gsold "uii'derthe trade na'me of 'j`Ga1' te)'; igl'ass; wood *andi various metals 'including' alu- Iron, copper; magnesium; nickel, tin, lead, etc., f* d multiplicity ofalloystniayalso be 'bonded'to polyhlorotriiiuoidethyieri and'the otheruorine containing L algnated* polyethyliiesfkiescribed 'by the "teachings -f-'embdie'd'in 'Eheim 'Senf invention.

:In Itisbelieved that the"chemical'"reactions of the phoshites -lass if suitable halogenated polyethylenes analogous to amin-ractions 'describedf in` lour i A licatfio';Serial'Ndg"344,398g'led March'24, u Q53',fvn'our.k tentNo `2,788,306,"ofvvhich the present f"`ap'plication is a divisiomind-ls'o iprovide afreebond for suitable adhesive. v A lsurfceof 'a fill dfonte ofthe I"suitable 1 atedpo'ly `ylen I's'fvvitl adhesives of limited polar- .bbergndfvarioiscrylates', methacryl- `ffaztcristitiz of substances polarity to Ybond to eachother. These matebelieved'fto "provide ,adhesion by means of "their Yability toflondon the"one"hand to the non-polar 1``fluorinated halogenated pglyethylenes and to adhere to eans of polar bonding on the other Ancl.- Inot'her'vy ds," ese' substances Iare suitable as 'Vadh'sives. The utilization of :these i'substances as adare' preferred.

lt has been dis eithattheA time 'required' for the treatmentfcanfberedced .tcinintes by raising the temperature. j l-oyjeverf'crtain substances are subgect to damage at theterlperat'rei'eqired for speedy treatment. These substances lineludefGaiite' and aluminum.

rHoweverin lieu ofraising'th'e temperature, irradiation by vjultraviolet light l'clurir'g"`tlc`""trieatient also accelerates .the desiredrrses- In ythervorkfwith ate, ultraviolet light Was used to accelerate the curingwftsone samples atJ room temperalture. Bonding of Trithneltojl'polyinethyl methacrylate t' and aluminum was also improved by'the'use of ultraviolet Mradiation. The incorpora ofdicetyl, as 'a vphotoifsensitizer, bestens the adhes1 n ofTrithene to` all of the 'above materials,m Any other suitable photosensitizer may i be sul:-stitt 1ted.;jA Thugiusirig'ilt'viole't' Vradiation for curing Trithene, 'bonding of 'Tiifhen 't' various materials may be accomplished satisfactorily utilizing polymerizable adhesives.

Ultraviolet irradiation is necessary to secure adhesion to aluminum and accelerates all other adhesions. The concentration of phosphite solution to be ulitized, the

duration of the treatment and the temperature at whichy the-*treatment takes place may be modified to insure tha-t'the treatment' is 'limited to the surface' only. Since a plurality of substances are suitable foruse in modifying'the surfaces' 'ofthe class ofh'alogenated ethylenes listed above, nogeneral rule; maybe statedfor the treatment in view of the wide range of characteristics .present in -the various products capable of reacting with n@the halogenatedl polyethylenes. 4Care'V should'be taken latter in: the phosphite'at' 1150 C. AAfter removal and washing,"` the sheet was successfully laminated to a' copolymer of methyl methacrylate'and methacrylic acid having amol ratio of 80 to2() 'by application of a slight pressure on glass plates on eachsideof the laminate.

IIL A po1ytrifluorochloroethylene` sheet was heated in dibutyl phosphite f or one hour at 150 C. The same treatment as that of Example I was used to adhere both Vvst irfacesof the-sheet4 to Lucite at contact pressure b'ty laminating for 1/2 hour atlSO"Y C. t Lamination resulted.

The following-materialswere also-tested and the results indicated these materials unsuitable Yfor modifying polytrifluorochloroethylene surfacesz AralditeAN-IOZ (Ciba) "Acryloid ALlOl (Rohm &Haas) (irlyptal'j i276v (General Electric) CycleweldlQ-ltl (Chrysler) Epen 1062"'(Shell) Polyamide Resinf f 93 ('Genera'lf"Mills) Polyamide ResirrSO (General Mills) Selectron 5 2 O8 (Pittsburgh Plate Glass) Selectron 5200` (Pittsburgh Plate Glass) N 1" (Piasburgh Pute (nass) G 92 (Pittsburgh Plate Glass) Y-s l (Pittsburgh Platel Glass) "Saran F4120 (Dow) Veicform F (Firestone) safari '1t- 11's (new) Neoprene KNR -(offrent) Rez-nglue (Schiri/arts) Poly n-butyl methacr'ylate Poly n-octyl methacrylate Poly n-octyl acrylate Y Poly isobutyl acrylate Divinyl benzeneln-hexylmethacylate copolymers Allyl triuoro acetate 4Allyl periluoro` b'uty'rate P- trichloro tertiary Bityl'lcohol Diallyl peruor succinate Difluoro dichloro ethyleepolymers Vinylidene Yur'ide` copolymers 'with acrylates and -methacrylates Copolymers 'ofiethyl""acylate'4 and beta-chloroe'thyl acrylate u Poly beta-chlbro'ethoxy ethyl metha'crylate i Polyheptauorobutyl acrylate Tri-allylcyanurate lfflev teachings ofsthe presenttinventionmake possible the use of the halcgenated and fluorinated polyethylenes listed above as protective coatings for containers for corrosive liquids, a typical example of which is depicted schematically in cross-section in Figure 3. Other suggested uses include protective coatings for bodies to be exposed to the effects of wind, weather, temperature variations, etc., in laminates where sheets of the non-polar substances comprise the outer sheets and in laminates Where a film of one of the non-polar substances comprises a thin interlayer, such as a safety window.

It is understood that the specific embodiments listed above have been described for illustration only and do not constitute the scope of the present invention, reference to the latter being contained in the accompanying claims.

The present application is a division of our copending application Serial No. 344,398 for Surface Treatment of Halogenated Fluoroethylenes and Laminates Thereof, filed March 24, 1953, now Patent No. 2,788,306.

What is claimed is:

l. An article of manufacture comprising a film produced by reacting a film of polymeric material whose surface is incapable of adhering effectively to other substances and having the general formula (-C2FnX4 n- ),n, where m equals a positive plural integer, n equals 2 or 3, and X is a halogen other than fluorine, with an organic phosphite capable of reacting with said polymeric material to improve its adhesive properties, and a layer of material subject to corrosion having a continuous surface adhesively bonded to said film.

2. An article of manufacture comprising a film produced by reacting a film of polymeric material having the general formula (-C2FnX4 n-)m, where m: equals a positive plural integer, n equals 2 or 3, and X is a halogen other than uorine, with an aliphatic phosphite, and a layer of material subject to corrosion having a continuous surface adhesively bonded to said film.

3. An article of manufacture comprising a film produced by reacting a film of polymeric material having the general formula C2PnX4 n-)m, where m equals a positive plural integer, n equals 2 or 3, and X is a halogen other than uorine, with an alkyl phosphite, and a layer of material subject to corrosion having a continuous surface adhesively bonded to said film.

4. An article of manufacture comprising a film produced by reacting a film of polymeric material having the general formula (-C2FnX4 n-)m, where mY equals a positive plural integer, n equals 2 or 3, and X is a halogen other than uorine, with dibutyl phosphite, and a layer of material subject to corrosion having a continuous surface adhesively bonded to said film.

5. A laminated article `in the form of a sheet comprising a film consisting essentially of the reaction product of polytriiiuorochloroethylene With an organic phosphite capable of reacting with polytrfluorochloroethylene to improve its adhesive properties, and a layer of material subject to corrosion having a continuous surface adhesively bonded to said film.

6. A laminated article in the form of a sheet comprising a film consisting essentially of the reaction product of polytriuorochloroethylene with an aliphatic phosphite and a layer of material subject to corrosion having a continuous surface adhesively bonded to said film.

7. A laminated article in the form of a sheet comprising a film consisting essentially of the reaction product of polytrifluorochloroethylene with an alkyl phosphite and a layer of material subject to corrosion having a continuous surface adhesively bonded to said lm.

8. A laminated article in the form of a sheet comprising a iilm consisting essentially of the reaction product of polytriuorochloroethylene with dibutyl phosphite and a layer of material subject to corrosion having a continuous surface adhesively bonded to said film.

9. A method of bonding a sheet of polymeric material whose surface is incapable of adhering effectively to other substances and having Ithe general formula (-C2FnX4n-)m, where m equals a positive plural integer, n equals 2 or 3, and X is a halogen other than uorine, to a base having a continuous surface composed of a material subject to corrosion comprising reacting a surface of said sheet with an organic phosphite capable of reacting with said polymeric material to improve its adhesive properties, applying an adhesive to one of said surfaces, and maintaining the surfaces in juxtaposition until the bond is cured.

10. The method according to claim 9, wherein the surfaces are maintained in juxtaposition in the presence of ultra-violet radiation.

1l. A container for corrosive agents comprising a body forming the bottom and sides of said container and a protective coating of a sheet of polymer whose surface is incapable of adhering effectively to other substances and having the general formula (-C2FnX4 n-)m, where m' equals a positive plural integer, nv equals 2 or 3, and X is a halogen other than uorine, adhesively bonded to at least the inner surface of said body, the surface of said coating facing said inner surface being composed of the reaction product of the sheet with an organic phosphite capable of reacting with said polymer to improve its adhesive properties.

l2. The article according to claim ll, wherein the sheet is composed of polytrifluoromonochloroethylene.

13. A laminated structure comprising `a plurality of relatively thick sheets of material having continuous inner surfaces, a relatively thin sheet of a polymeric material whose surface is incapable of adhering effectively to other substances and having the general formula where m equals a positive plural integer, n equals 2 or 3, and X is a halogen other than fluorine, between said inner surfaces, said thin sheet having a continuous surface chemically treated with an organic phosphite capable of reacting with said polymeric material to improve its adhesive properties, said continuous surfaces being adhesively bonded at their interfaces.

14. A laminated structure comprising a plurality of relatively thick sheets of rigid, transparent material having continuous inner surfaces, a relatively thin sheet of polymeric material whose surface is incapable of adhering effectively to other substances and having the general formula (-C2FnX4 n-)m, where mi equals a positive plural integer, n equals 2 or 3, and X is a halogen other than fluorine, between said inner surfaces, said thin sheet having a continuous surface chemically treated with an organic phosphite capable of reacting with said polymerio material to improve its adhesive properties, said continuous surfaces being adhesively bonded at their interfaces.

15. A laminated structure comprising a first sheet of material having continuous surfaces, a relatively thin sheet of polymeric material whose surface is incapable of adhering effectively to other substances and having the general formula (-C2FnX4 n-)m, where mi equals a positive plural integer, n equals 2 or 3, yand X is a halogen other than uorine, having a continuous surface chemically treated with an organic phosphite capable of reacting with said polymeric material to improve its adhesive properties facing each continuous surface of said first sheet, said continuous surfaces being adhesively bonded at their interfaces.

16. A laminated assembly comprising a sheet consisting essentially `of a substance from the class consisting of metals and metal alloys having a continuous surface, and a relatively thin sheet of polymeric material whose surface is incapable of adhering effectively to other substances and having the general formula (-C2FnX4 n-)m, where mi equals a positive plural integer, n equals 2 or 3, and X is a halogen other than fluorine, having a continuous surface adhesively bonded to said continuous surface of theyiirst sheet, said surfacefof the polymeric .-.1naterial nearestgsaid continuous surface` of therst sheet being composed of the reaction product of the polymer with an organic phosphite capable of reacting with said polymeric material .to improve its adhesive properties.

17. The laminated assemblyl according to claim 16, wherein ythe polymeric material is polytriuoromonochloroethylene.

18. The laminated assembly according wherein the phosphite is `dibutyl phosphite,

19,-The laminated assembly according wherein the substaneeis aluminum;`

20. The laminated assembly according. ,to claim f6, whereinfthesubstancey is magnesium.

21, A l'znninated assembly comprisingra pair of' glass sheets vhaving continuous inr1ersur fa :es, -a relatively thin sheet of polymeric-material .Whose surface is incapable of adhering eiectivelvto other substances and having the general formula Y (,-C2FnX4 n-)m Where-m-` eqnals a positiveplural integer,` n equals 2 or 3 and-Xiis Va halo- 'to claimv6,

to claim 6,

gen Lother than-fluorine between said inner surfaces, said thin sheet having a continuous surface chemically treated with lan organic -phosphite capable of reactingwith said polymeric, material to improve its adhesive properties, said continuoussurfacesbeing adhesively` bonded at their interfaces.

22. The laminated assembly according vto claim 21;, wherein vthe polymeric material is polytriuoromonochloroethylene.

References Cited in the le ofthis patent UNITED STATES `PATENTS t 2,559,749 Benning Y July l0, 1951 2,705,691 Panagrossi et al. Apr. 5,*1955 2,724,672 Rubin v a- Nov. 22,` 1955 OTHER REFERENCES Industrial and EngineeringChemistry, Iuly'195'3, `pages UNITED STATES PATENT OFFICE CERTIFICATIGN 0F CORRECTION Patent No@ 2,941,912 June 21Y 1960 Robert P., COX et aL Column 7, lines 9Y 11, and 13Si for the claim reference numeral "6", each occurrenceY read m- 16 lm.

Signed and sealed this 30th day of May 1961 (SEAL) Attest:

ERNEST W. SWIDER Attesting Officer DAVID L. LADD Commissioner of Patents 

1. AN ARTICLE OF MANUFACTURE COMPRISING A FLIM PRODUCED BY REACTING A FLIM OF POLYMERIC MATERIAL WHOSE SURFACE IS INCAPABLE OF ADHERING EFFECTIVELY TO OTHER SUBSTANCES AND HAVING THE GENERAL FORMULA (-C2FNX4-N-)M, WHERE M EQUALS A POSITIVE PLURAL INTEGER, N EQUALS 2 OR 3, AND X IS A HALOGEN OTHER THAN FLUORINE, WITH AN ORGANIC POSPHITE CAPABLE OF REACTING WITH SAID POLYMERIC MATERIAL TO IMPROVE ITS ADHESIVE PROPERTIES, AND A LAYER OF MATERIAL SUBJECT TO CORROSION HAVING A CONTINUOUS SURFACE ADHESIVELY BONDED TO SAID FILM. 